Validating facts is good too.
If the steak is blue and they ordered medium ... then there is little room for debate. If they wanted something other than what they ordered, then validating the feelings is more appropriate.
> then there is little room for debate
And that debate can be had (or not) by a lawyer or perhaps a manager, whose job it is to do so. No server is going to be vested with that authority, nor wants to be saddled with the uncompensated responsibility to.